The symptoms of schizophrenia vary widely from person to person but are defined under two international protocols known as DSM-IV TR and ICD-10. They are divided between “positive symptoms” – those where something happens in addition to normal life – and “negative symptoms” – those where something is taken away from everyday experience.
These fall into three main categories – not everyone with schizophrenia has all of these:
Delusions are firmly-held beliefs which are not held by most other people from the same background, culture or religion (if applicable) and can be quite bizarre e.g. being put under surveillance by MI5 (spies) or that a TV programme is about you. Indeed if someone has bizarre enough paranoid delusions then that is the only symptom required to be diagnosed with schizophrenia.
Hallucinations come in many forms but the most common are auditory hallucinations or “voices”. These can be unpleasant, such as “you smell”, or friendly, such as “you’re not a bad lad”. Approximately 4% of the population hear voices and it’s important to note that there is no compulsion to act on any instructions or “command hallucinations” in those who suffer these. Other types of hallucination exist including visual (seeing things that aren’t there) and olfactory (smelling things which aren’t there) and these can also be distressing.
Thought disorder is the least common positive symptom but is present sometimes during acute psychosis and is characterised by marked abnormalities in the flow and type of thoughts e.g. incomprehensible language that is presumed to reflect thinking.
These are characterised by a loss of interest, energy and emotions. Because these can be confused with depression, it is important that mental health professionals identify which are negative symptoms and which are depression, and that any depression is treated.
Examples of negative symptoms include not bothering to get up, or dressed, or leave the house. Someone with negative symptoms may not bother to cook, clean, tidy and change clothes. Negative symptoms are the main feature of one sub-type of schizophrenia – residual schizophrenia – and can be extremely tough to deal with (see below). Only one antipsychotic drug, clozapine (Clozaril), has been shown to have a significant impact on negative symptoms. Please see our section on Schizophrenia treatment.